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Vaisala CT25K User Manual

Manual is about: CEILOMETER

Summary of CT25K

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 26 february 1999 vaisala 1999.

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    © vaisala 1999 no part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder. The contents of instruction manuals are subject to c...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide i contents list of figures............................................................................................................ Iv introduction to manual ........................................................................................ Vii...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 ii 4.4.1 data message no. 1 ................................................................... 33 4.4.2 data message no. 2 ................................................................... 36 4.4.3 data message no. 3 ....................................

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide iii 7.1.2 instructions................................................................................. 89 7.2 troubleshooting .......................................................................................... 93 7.2.1 warnings ....................

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 iv list of figures figure 1-1 ceilometer ct25k ..........................................................................................1 figure 1-2 data line connection options.........................................................................5 ...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide v figure 5-15 ct25039 wiring diagram .......................................................................... 72 figure 5-16 ct3675 tilt angle sensor .......................................................................... 73 figure 5-17 window cond...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 vi this page intentionally left blank..

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide vii introduction to manual the purpose of this user’s guide is to be a general information source as well as a detailed operational guide for the user of ceilometer ct25k. This document is divided into 8 chapters. Chapter 1 offers an overview and techni...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 viii validity of this manual this manual covers ceilometer ct25k in all its configurations as defined by the parts and options listed in section 1.1, running under software revision ct25k- 2.01 or 2.01a table 1-1 lists the revision history that may appl...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide ix safety summary the following safety precautions must be observed during all phases of operation, service, and repair of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety stand...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 x ground the instrument to minimize shock hazard, the instrument chassis and cabinet must be connected to an electrical ground. The instrument is equipped with a three-conductor ac power connector. The power cable must either be plugged into an approved...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide xi internal heaters subassembly can be hot and has the following warning labels: dangerous procedure warnings warnings, such as the example below, precede potentially dangerous procedures throughout this manual. Instructions contained in the warnings mu...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 xii this page intentionally left blank..

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 1 1. General information 1.1 product overview ceilometer ct25k measures cloud heights and vertical visibilities. The small and lightweight measurement unit suits well for mobile operation. The ct25k ceilometer employs pulsed diode laser lidar technology...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 2 ceilometer ct25k consists of three main parts (figure 1-1): 1. Measurement unit including - optical subassembly ctb22 - laser transmitter ctt21 - receiver ctr21 - optics monitor ctl21 - frame dmf51 including - processor board dmc50b - dc converter dps...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 3 - shock absorber ct35022 for ship installations - pc terminal cable ct35198 to connect the connector of the rs-232 port of the pc to the maintenance port 1.2 specifications 1.2.1 mechanical dimensions: measurement unit 760 x 280 x 245 mm (30 x 11 x 10...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 4 power connector (j2): type binder series 693, 09-4223-00-04 4-pin (male) mating connector type: type binder series 693, 99-4222-70-04 (female) elbow no-break power supply 12v sealed lead acid battery, 2 ah overvoltage protection low-press filter , vdr...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 5 standard character frame: 1 start bit 7 data bits even parity 1 stop bit standard character code: usascii pin connections 1 rd- / an2lo 2 modem lead a / rxd / rd+ / an1hi 3 modem lead b / txd / sd+ / an1lo 4 signal ground 5 sd- / an2hi 6 +12 v dc supp...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 6 1.2.4.2 external connector j4 - maintenance line maintenance line is intended for on-site maintenance and can be used with ceilometer maintenance terminal, pc or other terminal. Connector (j3): type binder series 693, 09-4224-06-04 4-pin (male) mating...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 7 answer mode standard frequencies: v.21 bell 103 mark (1) 1650 hz 2225 hz space (0) 1850 hz 2025 hz originate mode optional signal level: -10 dbm (0.3 v) into 600 ohm standard (jumper selectable) max. Distance to operate 0...16 km (0...10 miles) with 2...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 8 1.2.6 transmitter laser source: indium gallium arsenide (ingaas) diode laser center wavelength: 905 ± 5 nm at 25 °c (77 °f) operating mode: pulsed nominal pulse properties at full range measurement: energy: 1.6 µ ws ± 20% (factory adjustment) peak pow...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 9 1.2.8 optical system optics system focal length: 377 mm (14.8 in.) effective lens diameter: 145 mm (5.7 in.) lens transmittance: 96 % typical window transmittance: 98 % typical, clean 1.2.9 performance measurement range: 0...25,000 ft. (0...7.5 km) re...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 10 2. Installation note before the installation, make sure that the ct25k configuration, especially line voltage setting, is in compliance with local circumstances. Information about the ct25k configuration in question is included in the delivery. 2.1 u...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 11 2.2 foundation the standard foundation for the ct25k ground installation is a concrete foundation. The minimum dimensions suggested are presented in figure 2-2. Mounting hardware is included with the delivery. Figure 2-2 foundation construction there...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 12 if the tilt feature will be used (see section 2.4), observe this in the layout of the foundation screws and pedestal placement. 2.3 assembling the unit the ct25k ceilometer is assembled in four stages: 1. Mount the pedestal on the foundation. 2. Atta...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 13 place the measurement unit on the pedestal flange. Attach the pedestal flange to the measurement unit by the two allen head screws with flat washers. An allen key is included in the delivery. Figure 2-4 attaching the measurement unit and the shield 3...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 14 2.4 using the tilt feature the measurement unit and pedestal of ceilometer ct25k are designed so that the unit can operate in a tilted direction. The built-in tilt angle sensor ct3675 detects the tilt angle, i.E. Deviation from the vertical. The tilt...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 15 as these advantages are partly contradictory and cannot or need not all be realized, the user must decide the final installation direction. In doing so, the following must be observed: note unless a tropics window is used, the unit must never be dire...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 16 • remote communication is normally connected to j3. • a local maintenance terminal, for example psion3, is intended to be connected to j4. A protective cap is included for covering j4 when not in use. External mating connectors with 2 m (7 ft.) cable...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 17 the ct25k is equipped with a separate grounding screw on the measurement unit flange for external earthing (see figure 2-4). Connection to a solid earth ground at the installation site is mandatory for adequate lightning and transient protection. 2.7...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 18 9. Exit from "comms" and select "save the setting" from "file" menu by name "ct25k". Now there should be the text "ct25k" under the "comms" application. From now on psion3 is ready to communicate with ct25k whenever "ct25k" from the "comms" applicati...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 19 3. Start up 3.1 start up procedure open the unit door; the key is included in the delivery. Make a visual check of the internal connectors, subassemblies, etc. Figure 3-1 describes the switches and leds needed to complete the start up procedure. 1. T...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 20 figure 3-1 ct25k switches and leds.

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 21 3.1.1 mobile operation aspects the small and lightweight ct25k ceilometer is suitable also for mobile operation. It has a built-in 12v battery, which enables operation without external power supply for about an hour in normal room temperature. Note f...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 22 3.3 settings for normal operation switch settings for normal operation are as follows: main circuit breaker f1 on window conditioner circuit breaker on battery switch on data message and interface configuration and the configuration of measuring inte...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 23 table 3-1 factory parameter settings response to user’s menu commands... Standard factory settings of user’s menu parameters notes ceilo>get... ...Data_acq autoadjustments: on data-acq. Interval: 15 sec. 15... 120 seconds available receiver gain: h b...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 24 ...Oper_mode operation mode: continuous option standby requires command start for carrying out each cycle. …options [modem name] sky condition: humitter: blower: installed inactive inactive active modem name is: dmx55, dmx50 or dmx611 active active i...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 25 4. Operation 4.1 operation modes there are two operation modes, continuous i.E. Normal and standby. Commands oper_mode standby and oper_mode continuous are used to switch between the modes. In normal mode continuous measurement and message transmissi...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 26 closed measurement data message transmitting state. In this state messages are transmitted automatically at predetermined intervals, or as a response to a polling input string, depending on the corresponding settings. User commands are not accepted, ...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 27 4.3 user commands user commands, command hierarchy and description are described in table 4- 1 below. User commands are accessible after opening the line by command open (no password needed). The command line interpreter provides interactive help sup...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 28 table 4-1 list of user and advanced level commands. Advanced level commands are marked bold. 1st (top) level 2nd level 3rd level 4th level 5th level description close release port for message transmission, i.E. Abort command dialog back back to norma...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 29 1st (top) level 2nd level 3rd level 4th level 5th level description set message angle_cor off angle correction: cloud and vertical visibility heights (distances) in messages are not corrected for the tilt angle on angle correction: cloud and vertical...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 30 1st (top) level 2nd level 3rd level 4th level 5th level description set oper_mode comp_monit run internal crosstalk compensation monitor until esc continuous operation mode: continuous measurement mode standby standby mode, no measurement unless comm...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 31 1st (top) level 2nd level 3rd level 4th level 5th level description set baud b300 set data port serial line baud rate to 300 b1200 set data port serial line baud rate to 1200 b2400 set data port serial line baud rate to 2400 b4800 set data port seria...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 32 1st (top) level 2nd level 3rd level 4th level 5th level description get value temperature blower print value of measured blower temperature, units: °c cpu print value of measured cpu board temperature, units: °c laser print value of measured laser te...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 33 4.4 data messages the following standard messages are provided: data message no. 1, 2, 3, 6 and 7. Anet / inet communication with dmx611. Status message s. Each port can be set to transmit a specified message automatically. Alternatively the port can...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 34 interpretation of the message is as follows : 1st line example: (cta2010j ↵ where ( start-of-heading character ct ceilometers’ identification string; always ct a unit number 0...9, a...Z 20 software level id 00...99 1 message number; this message is ...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 35 fedcba98 alarm (a), warning (w), and internal status information. Each character is a hexadecimal representation of four bits, altogether 32 bits (b00-b31), with the following breakdown. Interpretation as follows: f: b31 laser temperature shut-off (a...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 36 4.4.2 data message no. 2 data message no. 2 contains the range and sensitivity normalized backscatter profile within a range of 0..25000 ft, which makes it suitable for e.G. Graphical plotting of the atmosphere. Data resolution is 100ft = 30 m with d...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 37 interpretation of the message is as follows: 1st line identical to that of message no. 1 except that the second to last digit which identifies the message number is always 2. 2nd line identical to that of message no. 1 3rd line example: 100 n 53 +34 ...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 38 20th line l ↵ end-of-text and crlf. 4.4.3 data message no. 3 this message contains a line which has one bit for each range gate at 100 ft resolution. It is intended for printer-type black-and-white graphical recorders such as vaisala dr21, dr23, dd50...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 39 999 minimizes the threshold, and thus, maximizes recording sensitivity to a backscatter value of 100 / (10,000 km srad). 4th line identical to the 3rd line of message no. 3. 4.4.4 data message no. 4 data message no. 4 is not in use. 4.4.5 data messag...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 40 055 the second number of line: height of the 1st cloud layer (5 500 ft or 550 m depending on feet or meter selection) 5 the third number of line: cloud amount of the 2nd layer in oktas 170 the fourth number of line: height of the 2nd cloud layer (17 ...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 41 note "not enough data", i.E. Detection status 99, is reported after a start-up until the unit has operated for 25 minutes. "data missing", i.E. Detection status -1, is reported if more than 25% of gathered data is considered invalid due to a hardware...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 42 4.4.11 status message "s" the status message displays internal monitoring of the whole unit including prevailing parameter values for voltages, receiver and transmitter, temperatures, environmental factors, and internal heating. The message is meant ...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 43 lines 3...6 measured internal voltages in units of 0.1v, as follows: bat battery voltage, e.G. 098 cha battery charge voltage, e.G. 144 vca internal raw voltage, e.G. 225 phv receiver high voltage, e.G. 2306 pfb rec. Switcher feedback voltage, e.G. 1...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 44 lines 15...20 temperature and environment variables as follows: temperature blower +20c temperatue measured at the window conditioner blower airfow exit, e.G. +20 deg c cpu +34c temperature on the microprocessor (cpu) board, e.G. +34 deg c laser +29c...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 45 4.4.12 manual message the ceilometer can be set to transmit user defined cloud heights and status information. The user can set a cloud message in the format of line 2 of any real cloud message (e.G. Msg 1). The message must be between quotation mark...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 46 where enq is character enquire = ascii 05h = control-e ct is fixed ceilometer identifier id is identification character, 7-bit printable ascii character. No is optional message identifier 1, 2, 3, 6, 7, s ↵ enter (carriage return) + line feed polling...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 47 ceilo> get factory factory beamsplitter: 96% ** in laser: 185 ** out laser: 1200 ** coarse comp.: 13 ** fine comp.: 125 ** receiver test value: 350 ** clean window: 200mv ** ceilo> get message message angle correction: on height offset: 0 noise h2 co...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 48 ceilo> get status voltages (unit 0.1v) p12 130 m12 -122 p5g 53 m5g -54 vca 220 p13 126 m13 -121 p5r 49 m5r -48 bat 121 p18 176 phv 2755 pfb 20 p65 769 cha 121 receiver transmitter gain h plen l band n pqty 64k samp 10mhz out 1270mv sens ok sens 100% ...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 49 5. Functional description 5.1 theory of operation basic principle of operation the operating principle of the ct25k ceilometer is based on measurement of the time needed for a short pulse of light to traverse the atmosphere from the transmitter of th...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 50 in its normal full-range operation the ct25k ceilometer digitally samples the return signal every 100 ns from 0 to 50 µ s, providing a spatial resolution of 50 feet from ground to 25,000 feet distance. This resolution is adequate for measuring the at...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 51 height normalization assuming a clear atmosphere, it can be seen that the power is inversely proportional to the square of the distance or height i.E., the strength of a signal from 10,000 ft is generally one-hundredth of that from l,000 ft. The heig...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 52 extinction normalization and vertical visibility any fog, precipitation, or similar obstruction to vision between ground and cloud base may attenuate the cloud base signal and produce backscatter peaks that far exceed that from the cloud. Virtually a...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 53 5.2 technical description 5.2.1 general figure 5-2 below shows the internal layout of the measurement unit and the following figure 5-3 the subassembly interconnections. Summary of part num- bers and subassemblies is listed in table 5-1. The technica...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 54 figure 5-3 subassembly interconnections table 5-1 parts list part no. Description notes ct15035 enclosure ct35042 standard window ct35043 tropics window specified at order ctp241 line & pwr interface subassembly, ac 4592 battery.

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 55 ct25039 internal heaters subassembly ct3675 tilt angle sensor ctb22 optical subassembly ctt21 laser transmitter ctr21 receiver ctl21 optics monitor ct25015 compensation fiber dmf51 board frame dmc50b processor board dps52 dc converter board dct51 cei...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 56 normal (full range) mode characteristics: laser pulse 100 ns energy 1.6 µ j repetition rate 5.57 khz number of pulses 65,536 measurement time 11.7 s receiver on high gain bandwidth 3 mhz sampling at 100 ns 500 useful samples per laser pulse, measurem...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 57 when the measurement starts, the timing and control logic of the dct51 starts issuing trigger pulses to the laser transmitter ctt21 at the specified repetition rate. At each trigger pulse the transmitter sends out one laser pulse. This laser pulse ge...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 58 thus the resulting distortion is visible to the software in the raw measurement profile, and this is iteratively kept within limits. 5.2.3 internal monitoring and control all essential subassembly functions are monitored continuously to ensure measur...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 59 description the optical subassembly consists of the following major units: the conical optical tube with fixture for the lens, a precise beam integrator block at the lower end including a beamsplitter and a narrow-band filter, and a connection flange...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 60 small control circuit with a temperature sensor and a heating element ensures the correct laser temperature. The laser temperature is also routed to the ceilometer interface board dct51 and processor board dmc50b for internal monitoring. Warning dang...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 61 the flash ad converter. The gain control as well as the bandwidth selection are automatic and controlled by the processor software and the dct51. Warning dangerous voltages are present in this instrument. Use extreme caution when handling, testing, a...

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 62 delivers a control signal for the heating via an amplifier, processor board a- to-d converter, and software. 5.3.5 board frame dmf51 the frame dmf51 is a subassembly into which the processor board dmc50b, ceilometer interface board dct51, dc converte...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 63 the connections between the separate plug-in boards are realized by means of a motherboard and multiple board connectors. 5.3.6 processor board dmc50b figure 5-10 dmc50b block diagram.

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    Ceilometer ct25k user’s guide ct25k-u059en-2.1 64 the dmc50b processor board is the central processing unit of the ct25k. It performs the following functions: - a-to-d conversion of signals from various internal sensors - data processing under a powerful real-time operating system - serial communica...

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    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 65 technical information processor 16-bit 80c188eb, intel clock speed 24 mhz (12 mhz bus) memory flash eeprom 640 kb static ram 256 kb 1 mb continuous memory addressing a-to-d converter ± 12 bit accuracy 0.05 % of fsr speed 200 µ s / conversion gain con...

  • Page 80

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 66 see figure 5-11 and table 5-2 for dmc50 dip switch settings. Figure 5-11 dip switch settings of the dmc50 table 5-2 dip switch settings of the dmc50 board switch position switch setting function dmc50 s2-1 off disconnect digital gnd from case s2-2 on...

  • Page 81

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 67 5.3.7 dc converter dps52 the dps52 dc converter is an efficient and self-monitoring power distributor board specially designed for the ct25k. Having five independent switch-mode voltage converters the board is capable of delivering up to 20w. Figure ...

  • Page 82

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 68 all these voltages are normally supplied by two 18vac windings. The second supply rectified from two 10vac windings is reserved for internal battery charger, heating power for transmitter and inheater and outheatercontrol relays. All voltage and two ...

  • Page 83

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 69 output voltages: signal name acceptable range (v) nominal current(a) +5v 5.0 .. 5.8 0.15 -5v -5.8 .. –5.0 0.05 +5vdisc 5.0 .. 5.8 0.45 +18v 16.0 .. 18.5 0.010 +12v 12.0 .. 13.5 0.1 -12v -13.5 .. -11.5 0.1 +65v 60 .. 90 0.015 +13vr 12.0 .. 14.0 0.02 -...

  • Page 84

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 70 backscatter signal detected by the photodiode in the receiver is sampled in real-time in this subassembly at the speed equal to that of the light beam in the atmosphere sent from the laser transmitter. All range gates are sampled at each laser pulse ...

  • Page 85

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 71 figure 5-14 ctp241 wiring line voltage selection 100...115 vac or 220...240 vac is carried out in the ctp241 by an internal switch, the setting of which is written on the label on the subassembly. This setting also accomplishes the series vs. Paralle...

  • Page 86

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 72 5.3.10 internal heaters subassembly ct25039 figure 5-15 ct25039 wiring diagram the internal heaters subassembly ct25039 increases the temperature in the area of the optical subassembly to prevent the lens and the measurement unit window from becoming...

  • Page 87

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 73 thermal switches (k1, k2): - switch temperature 95 - 105 ° c - nominal current 2.5a - operating voltage 250vac 5.3.11 tilt angle sensor ct3675 the built-in tilt angle sensor ct3675 enables accurate cloud base measurements in a tilted direction. See s...

  • Page 88

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 74 5.3.12 window conditioner ct2614 / ct2688 figure 5-17 window conditioner ct2614/ct2688.

  • Page 89

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 75 the window conditioner consists of a blower motor, heating element and an ntc temperature sensor inside an enclosure. The air stream from the blower is directed across the measurement unit window for clearing it from water drops, condensed humidity, ...

  • Page 90

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 76 standard port settings are the following: baud rate 2400 data bits 7 stop bits 1 parity even ignore parity yes for setting up psion3 see section 2.7 connection of maintenance terminal. For further information about psion3 and series 3 serial link see...

  • Page 91

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 77 safety precautions before delivery, the dmx55 modem is tested at the factory for operation and safety. The following safety precautions, however, must be taken into account: warning open data lines can have a static charge. Handle the connection wire...

  • Page 92

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 78 11-pin connector (p1) 1 +int +interrupt 2 -int -interrupt 3 n.C. Normal closed 4 com. Relay common 5 n.O. Normal open 6&7 line in line in - when separate transmission and reception lines are used (4-wire connection) 8&9 line out line in/out - when st...

  • Page 93

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 79 safety precautions before delivery, the dmx50 modem is tested at the factory for operation and safety. The following safety precautions, however, must be taken into account: warning open data lines can have a static charge. Handle the connection wire...

  • Page 94

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 80 4-pin connector: this connector carries telephone line audio signals for special applications, and shall not be connected when the dmx50 is to be used over public telephone lines. 6-pin connector: for line connection. The attached modular telephone c...

  • Page 95

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 81 txd this led will flash whenever the dmx611 sends data to the ct25k (or to any device attached to the front panel txd output). Connector layout phone jack the front panel has a six pin modular phone jack, that is labeled test. It is designed for a ha...

  • Page 97

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 83 5.4 sky condition algorithm 5.4.1 general the ct25k sky condition algorithm uses a time series of ceilometer data to calculate the cloud cover and the heights of different cloud layers. The algorithm is based on so-called larsson algorithm, developed...

  • Page 98

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 84 then select the sky condition message type (msg6 or msg7) to be reported: ceilo>set message type msg6 message type: 6 ceilo>close note it is recommended to use a 15 or 30 seconds data acquisition interval with the sky condition option. 5.4.4 algorith...

  • Page 99

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 85 the counts are summed starting from the lowest bin. The bins where the sum exceeds 1/33, 3/8, 5/8 and 7/8 of the maximum value are recorded as layer heights. The corresponding cloud amounts for these layers are 1,3,5 and 7 oktas. In addition, the min...

  • Page 100

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 86 overcast (8 oktas) is reported if all the measurements during the last 30 minutes have a hit. Overcast height is assigned according to the bin where 14/15 of the total count value is exceeded. However, overcast is not reported if there are "weak hits...

  • Page 101

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 87 6. Periodic maintenance periodic maintenance is normally limited to window cleaning. In addition, warnings and alarms should be checked regularly with the maintenance terminal or another terminal or pc with serial connection (see paragraph 4.4.11 sta...

  • Page 102

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 88 the door of the measurement unit utilizes an electrically conductive rubber gasket to suppress electromagnetic radiation. When the door is opened, check that the gasket and the opposite contact surface are clean. Use wet cloth for cleaning if necessa...

  • Page 103

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 89 7. Troubleshooting 7.1 normal operation 7.1.1 equipment to check the normal operation of the ct25k you need to have a maintenance terminal which can be a psion3 palmtop computer with an rs cable (rs232 interface) and terminal cable ct3840 or a pc wit...

  • Page 104

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 90 press enter. The prompt "ct:" should appear on the screen. If not, check the cables and port settings (see ct-view user’s guide). 4. Check that the operation of the ceilometer starts normally, as follows: after power-up routines, the meas led d4 (led...

  • Page 105

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 91 6. Check the status message. All the voltages, receiver and transmitter values are within predefined limits if no asterisks (*) appear. An asterisk in front of a variable indicates that an alarm or warning limit of that variable is exceeded. In the s...

  • Page 106

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 92 d: (0080 0000) window contaminated (w) (0040 0000) battery low (w) (0020 0000) laser power low (w) (0010 0000) laser temperature high or low (w) c: (0008 0000) internal temperature high or low (w) (0004 0000) voltage high or low (w) (0002 0000) relat...

  • Page 107

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 93 note the minimum distance to a hard target should be 300 meters (1,000 ft). The backscatter signal from a hard target is very strong compared to the signal from a cloud. The receiver may saturate if the distance is too short. Caution when tilting the...

  • Page 108

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 94 battery low warning the unit has been powered too long using the backup battery connect the line voltage or replace the battery recharging of the battery fails if the battery is old, replace it. If the battery is ok, check the operation of the dps52 ...

  • Page 109

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 95 relative humidity > 85 % warning (option) water has been condensed inside the ceilometer. Leakage in the enclosure or leakage in the door take the ceilometer inside, open the maintenance door and let it dry in a warm air conditioned place. Condensed ...

  • Page 110

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 96 7.2.2 alarms problem reason instructions laser temperature shut- off direct sunlight direct sunlight can burn the laser diode. Use tropics window or turn the ceilometer away. Environment temperature too high do not operate the ceilometer. Laser failu...

  • Page 111

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 97 7.2.3 miscellaneous problem reason instructions dps52 power ok led (d2) is not lit power is not connected check that both the main and the battery switches are in on position. Check the presence and correctness of the line voltage. Check also that th...

  • Page 112

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 98 7.3 failure diagnosis in case of malfunction do the following: 1. Check the cable connections (see 2.5). 2. Check the presence and correctness of the line voltage. 3. Check the operation states of the leds in the unit (see 3.1). 4. At the data line, ...

  • Page 113

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 99 8. Repair 8.1 general replacing a subassembly comes into question when there is reason to suspect that malfunction of the ceilometer ct25k is caused by a fault in that subassembly. Caution servicing the equipment must be performed by qualified person...

  • Page 114

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 100 8.3 start-up procedure for replacement (all parts) replacement can be done outdoors even in the presence of light precipitation but in this case take care that the removed subassembly remains dry and no water gets into the interior of the ceilometer...

  • Page 115

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 101 refer to figure 8-1 for cable connections of the subassemblies. Figure 8-1 board connectors of the dmf51 board frame 8.4 transmitter ctt21 8.4.1 removal warning the laser diode at laser transmitter ctt21 emits invisible laser power which is harmful ...

  • Page 116

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 102 when there is reason to suspect malfunction of the transmitter, turn the power off (note paragraph 8.3 start-up procedure) and do as follows: 1. Detach the ribbon cable connector of the transmitter from connector j10 at the dmf51 board frame by pres...

  • Page 117

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 103 check that the transmitter is now in the correct position, that is, the sides of the transmitter case are approx. Parallel with the edges of the lower part of the optical subassembly. If this is not the case, loosen the attachment ring first, then c...

  • Page 118

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 104 f) wait until a few measurement cycles have been completed, and the new value has been updated in the status message. Give the command get status ↵ g) check from the status message under the title transmitter that the in value of the transmitter in ...

  • Page 119

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 105 8.4.3 compensation adjustments internal crosstalk compensation must be adjusted after a transmitter, a receiver or an optics monitor has been replaced or if the compensation fiber has been replaced. Adjustment should be done in clear weather conditi...

  • Page 120

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 106 figure 8-3 adjusting the compensation adjusting should not require more than a couple of turns. The screw should not move too easily after the adjustment has been completed. If a locking nut is in place, tighten it. In case the graph does not get op...

  • Page 121

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 107 figure 8-4 adjusting the compensation 5. Set the autoadjustments on with the following command: set data_acq autoadj on ↵ 6. Wait for some minutes. Give the command get status ↵ check from the status message under the title receiver that the comp va...

  • Page 122

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 108 if this value remains in the range 300...400, it is acceptable. 7. Wait again for at least one measurement cycle (15 seconds), and give the get status command. Check once more from the status message the receiver comp values. These should be the sam...

  • Page 123

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 109 figure 8-5 removing the receiver 8.5.2 replacement to replace receiver ctr21 (note paragraph 8.3 start-up procedure): 1. Attach the coaxial cable to connector j2 at the receiver. Note the marked ends of the cable. 2. Take the receiver into your hand...

  • Page 124

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 110 check that the receiver is now in the correct position, that is, the long edges of the receiver case are approx. Horizontal. If this is not the case, loosen the attachment ring first, then correct the receiver position and fasten as described above....

  • Page 125

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 111 check that the sens value is ok. The receiver sensitivity tells you the present measured receiver value compared to the factory setting. If the sens value is ok, the receiver installation is ready and you can skip steps g) and h). G) if the sens val...

  • Page 126

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 112 2. Detach the ribbon cable connector of the receiver from the connector j11 at the dmf51 board frame. Refer to figure 8-1. 3. Detach the coaxial cable from the dct51 front panel. 4. Loosen the ctr21 receiver attachment ring (see figure 8-5) using a ...

  • Page 127

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 113 8.6 compensation fiber 8.6.1 compensation fiber replacement the compensation fiber is made from optical fiber. Handle the fiber with care. Don’t twist. Do not allow the ends of the fiber to be contaminated by grease or dust. When there is reason to ...

  • Page 128

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 114 note if you run into trouble performing step 8 above, such that the adjustment is not finished because screw b has already traveled all the way out from the receiver, you also have to adjust the other end of the fiber. (this can be quite laborious.)...

  • Page 129

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 115 figure 8-6 removing the optics monitor 8.7.2 replacement to replace optics monitor ctl21: 1. Fasten the optics monitor ctl21 to the ceilometer with two screws (figure 8-6). The previous horizontal position of the ctl21 is a good estimate of the corr...

  • Page 130

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 116 8.8 boards of board frame dmf51 the boards of board frame dmf51 are shown in figure 8-7. Replacement of boards does not require parameter settings except the ceilometer interface board dct51, the adjustments of which are described in paragraph 8.8.2...

  • Page 131

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 117 8.8.2 replacing boards 1. Plug the new board carefully into the corresponding slot (figure 8-7). 2. Attach the new board with the two screws. Then plug in connectors. Cable connections were described in paragraph 2.5. 3. When the ceilometer interfac...

  • Page 132

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 118 note if the ceilometer is installed outdoors and a replacement unit is not immediately available, it is advisable either to bring the unit indoors or cover the exposed opening with tape to protect the interior against water, insects. Etc. 1. If the ...

  • Page 133

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 119 figure 8-8 removing line and power interface subassembly ctp241 8.9.2 replacement warning the line & power subassembly contains dangerous voltage of 115 vac/230 vac even when the power switch f1 is turned off. Do not connect the power cable to an un...

  • Page 134

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 120 7. Turn the 6 screws at the bottom of the ct25k clockwise (figure 8-8) and push then slightly until they go through the holes in the gasket of the connector flange. Then tighten the screws normally. 8. Tighten the screw that connects the ctp241 to t...

  • Page 135

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 121 figure 8-9 internal heater replacement 8.9.4 battery 4592 replacement instructions 1. Open the screw from the battery switch subassembly front panel shown in figure 8-10 and remove the panel. 2. Pull the battery out by the plastic stripe attached ar...

  • Page 136

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 122 figure 8-10 battery replacement.

  • Page 137

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 123 index a alarm check ...................................................87 alarms laser failure ...............................................96 laser temperature shut-off..........................96 receiver failure ...................................

  • Page 138

    Ceilometer ct25k user’s guide ct25k-u059en-2.1 124 h hard target test............................................... 92 hardware history........................................... Viii height normalization...................................... 51 i infrared interference filter .........................

  • Page 139

    Ceilometer ct25k ct25k-u059en-2.1 user’s guide 125 pulse properties ................................................8 r receiver ...........................................................8 receiver ctr21 .............................................60 coaxial cable replacement ........................